PQMon: a powerful veto for burst events

Data taken by the gravitational wave detector GEO 600 (Danzmann K et al 1994 GEO 600—Proposal for a 600m Laser-Interferometric Gravitational Wave Antenna (Garching: MPQ)) during the science run 'S1' contain a large number of transients. In order to reduce the false-alarm rate of burst gravitational wave search algorithms it is desirable to veto all those transients that are clearly not of gravitational wave origin. This paper presents a method of vetoing transients by looking at the 'in-phase' ( P ) and 'quadrature' ( Q ) channels of the demodulated interferometer output signal. By taking advantage of the fact that the P -channel and the Q -channel have different sensitivities to gravitational wave burst events, this method can veto transients that have a power distribution different from the signature of a signal induced by a gravitational wave.